✍🏼 Adriana Ponton-Almodovar, Mary P. Udumula, Vrinda Khullar, Faraz Rashid, Ramandeep Rattan, Jamie J. Bernard & Sachi Horibata

🏠 Precision Health Program, Michigan State University, East Lansing, MI, USA

📑 Scientific Reports (2025)

Abstract
Metabolic reprogramming is recognized as a hallmark of cancer frequently associated with drug resistance in ovarian cancer. This is problematic as ovarian cancer is one of the deadliest gynecologic cancers with platinum resistance contributing to poor survival. However, the mechanism by which ovarian cancer cell metabolism contributes to platinum resistance is not well understood. Herein, metabolic signatures were determined in platinum-resistant ovarian cancer cell lines compared to the more platinum-sensitive parental lines. Chemoresistant ovarian cancer cells showed increased oxidative phosphorylation (OXPHOS) compared to chemosensitive cells. This was associated with elevated levels of glutaminolysis and tricarboxylic acid (TCA)-related metabolites supporting their dependence on OXPHOS. Key enzymes involved in glutaminolysis, specifically, glutamic-pyruvic transaminase 2 (GPT2), were upregulated in chemoresistant compared to chemosensitive cells. Interestingly, high GPT2 gene expression is associated with worse prognosis in ovarian cancer patients, adding translational relevance to the pre-clinical findings. GPT2 knockout in chemoresistant cells restored the metabolic phenotype to that of the sensitive cells and reversed drug resistance. These data suggest that GPT2 is a critical link between glutaminolysis, the TCA cycle, and OXPHOS and is a potential target to attenuate the increased metabolic activity associated with a chemoresistant phenotype.

How the WOLF was used in this study
The WOLF Cell Sorter was used as part of the process to generate and isolate clonal cell populations following CRISPR/Cas9-mediated knockout of the GPT2 gene. After transfection of chemoresistant ovarian cancer cells with CRISPR constructs targeting GPT2, the WOLF sorter was employed to select and purify individual cells that had incorporated the editing constructs and to establish monoclonal lines for downstream validation and functional assays. This sorting step enabled the researchers to obtain homogeneous cell populations for accurate metabolic profiling and comparative analyses between GPT2 knockout and control clones, which was critical for linking GPT2 loss to changes in glutamine metabolism and drug sensitivity.